Nitrous Oxide and Serious Long-term Morbidity and Mortality in the Evaluation of Nitrous Oxide in the Gas Mixture for Anaesthesia (ENIGMA)-II Trial. Categories: Nitrous Oxide Author: Beattie WS, Chan MT, Devereaux PJ, Forbes A, Kasza J, Leslie K., Myles PS, Paech MJ, Peyton PJ, Sessler DI, Wallace S